The Initial Stage of Canine Endotoxin Shock as an Expression of Anaphylactic Shock: Studies on Complement Titers and Plasma Histamine Concentrations*

Open Access
Publisher Website
Google Scholar
Abstract
Experimental data in canine endotoxin shock support the concept that the initial stage of hemodynamic alterations is due to an anaphylactic type of immune mechanism involving complement, with the liberation of histamine. However, the severity of the systemic reaction is not indicative of the final outcome of animals. Epsilon-aminocaproic acid and cortisol modify the severity of the initial reaction and the majority of animals survive lethal doses of endotoxin. On the other hand, surviving animals given a second lethal dose of endotoxin have a severe initial reaction, a significant decline in complement, and a marked rise in plasma histamine. The majority of these animals also survive. Finally, dogs infused with histamine survive a lethal dose of endotoxin. The relationship of the initial anaphylactic activity to the ultimate outcome of an animal with endotoxin shock is not clear. Tolerance or intolerance to the lethal action of endotoxin is dependent upon other mechanisms and may be related to acquired humoral immunity and conditioning of the reticuloendothelial system.